Friday, July 24, 2009

Scientific and Recreational Diving in Thunder Bay National Marine Sanctuary

Thunder Bay National Marine Sanctuary (TBNMS) is primarily known for its vast number of shipwrecks. An estimated 200 shipwrecks reside within and just outside the sanctuary’s waters. These wrecks range from nineteenth century lake schooners and paddleboats to perhaps Thunder Bay’s last wreck, the German freighter Nordmeer, which wrecked near Thunder Bay Island in 1966.

Each year hundreds of recreational divers come to TBNMS to brave the chilly waters of Lake Huron for a chance to glimpse sunken history. In addition to the recreational divers, the sanctuary has a team of scientific and archaeological divers working to protect, preserve and learn more about the sanctuary’s known wrecks as well as research and explore for undiscovered wrecks.

Scientific diving requires additional skills and training above and beyond what is required for a typical recreational diver. While diving to depths greater than 30 meters can be considered advanced for a recreational diver, imagine having to dive to that depth and greater to set up equipment or take samples!

The chilly water temperatures of Lake Huron also require divers to use dry-suits almost all year long. Water near the bottom of the Middle Island Sinkhole in early September is a brisk 38 degrees Fahrenheit!

TBNMS divers have played an important role in sinkhole exploration. Scientists depend on the divers to collect samples of the purple and white microbial mats at the bottom of the sinkhole and deploy and position instrumentation, such as the respiration chambers and tripods for accurate data collection. Divers also provide underwater photographs and video of the sinkholes.